Tolerance
Analyse Mother Teresa's DNA and that of a mass killer. What makes them different is not noticable, at this level they would have approximately 99% commonality.
Their differences can only be measured through the effects of their actions. One acts with Love. The other is driven by anger, hatred and fear.
I read about a boy who was well educated, loved, middle class but who killed his girlfriend and it was found had tied a dog to a tree and stoned it to death. That's pretty nasty. Yet this same boy was widely known in his small town to be well liked, courteous, thoughtful. A boy almost like any other. Almost. Outward appearances don't always reflect what might be missing within a human heart. What is missing is tolerance.
Tolerance is not just a good idea, it is a highly dynamic virtue.
The practice of tolerance is based on love - for oneself, for others, and for the whole universe. When we actively remember that not only do we ourselves have such an 'immortal centre', but so does every other human being - it softens how we think about tolerance. When we see within others a core of love that is common to our own inner core then the true secret and beauty of that person's soul is revealed to us.
Intolerance is symptomatic of fear, ignorance, bitterness. It can also express fear, envy and rage that someone has what you do not. If tolerance towards others is going to exist it must be based on the conscious cultivation of tolerance towards yourself to begin with, then towards others and equally. To the Universe we must also be tolerant because afterall, do we know the big picture?
Tolerance allows you to develop a frame of mind that forgives yourself and others that speaks to fear in the language of love. To love fear has no answer.